diff options
| -rw-r--r-- | source/fitz/ftoa.c | 332 |
1 files changed, 22 insertions, 310 deletions
diff --git a/source/fitz/ftoa.c b/source/fitz/ftoa.c index 355f0879..92ee9edf 100644 --- a/source/fitz/ftoa.c +++ b/source/fitz/ftoa.c @@ -1,178 +1,5 @@ -/* The authors of this software are Rob Pike and Ken Thompson. - * Copyright (c) 2002 by Lucent Technologies. - * Permission to use, copy, modify, and distribute this software for any - * purpose without fee is hereby granted, provided that this entire notice - * is included in all copies of any software which is or includes a copy - * or modification of this software and in all copies of the supporting - * documentation for such software. - * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED - * WARRANTY. IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE ANY - * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY - * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE. - */ - #include "mupdf/fitz.h" -#include <stdio.h> -#include <math.h> -#include <float.h> -#include <string.h> -#include <stdlib.h> -#include <errno.h> - -#ifndef INFINITY -#define INFINITY (DBL_MAX+DBL_MAX) -#endif -#ifndef NAN -#define NAN (INFINITY-INFINITY) -#endif - -#ifndef DEFINED_ULONG -#define DEFINED_ULONG -typedef unsigned long ulong; -#endif - -enum { NSIGNIF = 9 }; - -/* - * first few powers of 10 - */ -static float pows10[] = -{ - 1e0f, 1e1f, 1e2f, 1e3f, 1e4f, 1e5f, 1e6f, 1e7f, 1e8f, 1e9f, - 1e10f, 1e11f, 1e12f, 1e13f, 1e14f, 1e15f, 1e16f, 1e17f, 1e18f, 1e19f, - 1e20f, 1e21f, 1e22f, 1e23f, 1e24f, 1e25f, 1e26f, 1e27f, 1e28f, 1e29f, - 1e30f, 1e31f, 1e32f, 1e33f, 1e34f, 1e35f, 1e36f, 1e37f, 1e38f -}; -#define npows10 ((int)(sizeof(pows10)/sizeof(pows10[0]))) -#define pow10(x) fmtpow10(x) - -static float -pow10(int n) -{ - float d; - int neg; - - neg = 0; - if(n < 0){ - neg = 1; - n = -n; - } - - if(n < npows10) - d = pows10[n]; - else{ - d = pows10[npows10-1]; - for(;;){ - n -= npows10 - 1; - if(n < npows10){ - d *= pows10[n]; - break; - } - d *= pows10[npows10 - 1]; - } - } - if(neg) - return 1./d; - return d; -} - -/* - * add 1 to the decimal integer string a of length n. - * if 99999 overflows into 10000, return 1 to tell caller - * to move the virtual decimal point. - */ -static int -xadd1(char *a, int n) -{ - char *b; - int c; - - if(n < 0 || n > NSIGNIF) - return 0; - for(b = a+n-1; b >= a; b--) { - c = *b + 1; - if(c <= '9') { - *b = c; - return 0; - } - *b = '0'; - } - /* - * need to overflow adding digit. - * shift number down and insert 1 at beginning. - * decimal is known to be 0s or we wouldn't - * have gotten this far. (e.g., 99999+1 => 00000) - */ - a[0] = '1'; - return 1; -} - -/* - * subtract 1 from the decimal integer string a. - * if 10000 underflows into 09999, make it 99999 - * and return 1 to tell caller to move the virtual - * decimal point. this way, xsub1 is inverse of xadd1. - */ -static int -xsub1(char *a, int n) -{ - char *b; - int c; - - if(n < 0 || n > NSIGNIF) - return 0; - for(b = a+n-1; b >= a; b--) { - c = *b - 1; - if(c >= '0') { - if(c == '0' && b == a) { - /* - * just zeroed the top digit; shift everyone up. - * decimal is known to be 9s or we wouldn't - * have gotten this far. (e.g., 10000-1 => 09999) - */ - *b = '9'; - return 1; - } - *b = c; - return 0; - } - *b = '9'; - } - /* - * can't get here. the number a is always normalized - * so that it has a nonzero first digit. - */ - return 0; -} - -/* - * format exponent like sprintf(p, "e%+d", e) - */ -static void -fmtexp(char *p, int e) -{ - char se[9]; - int i; - - *p++ = 'e'; - if(e < 0) { - *p++ = '-'; - e = -e; - } else - *p++ = '+'; - i = 0; - while(e) { - se[i++] = e % 10 + '0'; - e /= 10; - } - while(i < 1) - se[i++] = '0'; - while(i > 0) - *p++ = se[--i]; - *p++ = '\0'; -} - /* * compute decimal integer m, exp such that: * f = m*10^exp @@ -182,149 +9,34 @@ fmtexp(char *p, int e) void fz_ftoa(float f, char *s, int *exp, int *neg, int *ns) { - int c, d, e2, e, ee, i, ndigit, oerrno; - char tmp[NSIGNIF+10]; - float g; - - oerrno = errno; /* in case strtod smashes errno */ - - /* - * make f non-negative. - */ - *neg = 0; - if(f < 0) { - f = -f; - *neg = 1; - } - - /* - * must handle zero specially. - */ - if(f == 0){ - *exp = 0; - s[0] = '0'; - s[1] = '\0'; - *ns = 1; - return; - } - - /* - * find g,e such that f = g*10^e. - * guess 10-exponent using 2-exponent, then fine tune. - */ - frexpf(f, &e2); - e = (int)(e2 * .301029995664f); - g = f * pow10(-e); - while(g < 1) { - e--; - g = f * pow10(-e); - } - while(g >= 10) { - e++; - g = f * pow10(-e); - } - - /* - * convert NSIGNIF digits as a first approximation. - */ - for(i=0; i<NSIGNIF; i++) { - d = (int)g; - s[i] = d+'0'; - g = (g-d) * 10; - } - s[i] = 0; - - /* - * adjust e because s is 314159... not 3.14159... - */ - e -= NSIGNIF-1; - fmtexp(s+NSIGNIF, e); - - /* - * adjust conversion until strtod(s) == f exactly. - */ - for(i=0; i<10; i++) { - g = fz_strtod(s, NULL); - if(f > g) { - if(xadd1(s, NSIGNIF)) { - /* gained a digit */ - e--; - fmtexp(s+NSIGNIF, e); - } - continue; - } - if(f < g) { - if(xsub1(s, NSIGNIF)) { - /* lost a digit */ - e++; - fmtexp(s+NSIGNIF, e); - } - continue; - } - break; - } - - /* - * play with the decimal to try to simplify. - */ + char buf[40], *p = buf; + int i; - /* - * bump last few digits up to 9 if we can - */ - for(i=NSIGNIF-1; i>=NSIGNIF-3; i--) { - c = s[i]; - if(c != '9') { - s[i] = '9'; - g = fz_strtod(s, NULL); - if(g != f) { - s[i] = c; - break; - } - } + for (i = 0; i < 10; ++i) + { + sprintf(buf, "%.*e", i, f); + if (fz_atof(buf) == f) + break; } - /* - * add 1 in hopes of turning 9s to 0s - */ - if(s[NSIGNIF-1] == '9') { - strcpy(tmp, s); - ee = e; - if(xadd1(tmp, NSIGNIF)) { - ee--; - fmtexp(tmp+NSIGNIF, ee); - } - g = fz_strtod(tmp, NULL); - if(g == f) { - strcpy(s, tmp); - e = ee; - } + if (*p == '-') + { + *neg = 1; + ++p; } + else + *neg = 0; - /* - * bump last few digits down to 0 as we can. - */ - for(i=NSIGNIF-1; i>=NSIGNIF-3; i--) { - c = s[i]; - if(c != '0') { - s[i] = '0'; - g = fz_strtod(s, NULL); - if(g != f) { - s[i] = c; - break; - } + *ns = 0; + while (*p && *p != 'e') + { + if (*p >= '0' && *p <= '9') + { + *ns += 1; + *s++ = *p; } + ++p; } - /* - * remove trailing zeros. - */ - ndigit = NSIGNIF; - while(ndigit > 1 && s[ndigit-1] == '0'){ - e++; - --ndigit; - } - s[ndigit] = 0; - *exp = e; - *ns = ndigit; - errno = oerrno; + *exp = fz_atoi(p+1) - (*ns) + 1; } |